Systems and methods for thermal management of an information handling system including cooling for third-party information handling resource

ABSTRACT

In accordance with these and other embodiments of the present disclosure, a system may include a plurality of temperature sensors configured to sense temperatures at a plurality of locations associated with an information handling system, a cooling subsystem comprising at least one cooling fan configured to generate a cooling airflow in the information handling system, and a thermal manager communicatively coupled to the plurality of temperature sensors and the cooling subsystem. The thermal manager may be configured to, based on at least a power provided to a subsystem of the information handling system, estimate a thermal condition proximate to the subsystem, based on a maximum power consumption for a component of the subsystem, determine an estimated linear airflow velocity requirement for the component, and set a speed of the at least one cooling fan based on the estimated thermal condition and the estimated linear airflow velocity requirement.

TECHNICAL FIELD

The present disclosure relates in general to information handlingsystems, and more particularly to thermal management of an informationhandling system at a modular level.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

As processors, graphics cards, random access memory (RAM) and othercomponents in information handling systems have increased in clock speedand power consumption, the amount of heat produced by such components asa side-effect of normal operation has also increased. Often, thetemperatures of these components need to be kept within a reasonablerange to prevent overheating, instability, malfunction and damageleading to a shortened component lifespan. Accordingly, thermalmanagement systems including air movers (e.g., cooling fans and blowers)have often been used in information handling systems to cool informationhandling systems and their components. Various input parameters to athermal management system, such as measurements from temperature sensorsand inventories of information handling system components are oftenutilized by thermal management systems to control air movers and/orthrottle power consumption of components in order to provide adequatecooling of components.

However, instances may exist in which a thermal management system maynot have sufficient input parameters in order to adequately determinethermal health of various components. For example, Peripheral ComponentInterconnect (PCI) and other input/output (I/O) cards are a commonexample of a component that in many typical information handling systemtopologies, lacks sufficient thermal data in order for efficient thermalcontrol. Thermal control of many such cards typically includesgenerating an automatic or manually-configured predefined air moverresponse which is static in nature and does not dynamically take intoaccount varying thermal parameters of an information handling system. Adisadvantage of this approach is that it must assume a worst-casescenario, meaning more airflow may be used to cool such I/O cards thanmay actually be required to operate correctly, leading to wastedelectrical power required to operate air movers. Another disadvantage ofthis approach is that expecting users to manually configure coolinglevels for I/O card cooling may be risky and may provide a bad userexperience.

As another example, many information handling system components may notbe capable of reporting their temperatures. Accordingly, thermalmanagement of such components may include setting minimum open loop airmover speeds which may be defined based on system characterizationduring design and development of an information handling system, and mayrequire extensive testing to determine optimum air mover speeds.

SUMMARY

In accordance with the teachings of the present disclosure,disadvantages and problems associated with thermal management of aninformation handling system may be reduced or eliminated.

In accordance with embodiments of the present disclosure, a system mayinclude a plurality of temperature sensors configured to sensetemperatures at a plurality of locations associated with an informationhandling system, a cooling subsystem comprising at least one cooling fanconfigured to generate a cooling airflow in the information handlingsystem and a thermal manager communicatively coupled to the plurality oftemperature sensors and the cooling subsystem. The thermal manager maybe configured to, based on at least a power provided to a subsystem ofthe information handling system, estimate a thermal condition proximateto the subsystem and set a speed of the at least one cooling fan basedon the estimated thermal condition and a required linear airflowvelocity associated with the subsystem.

In accordance with these and other embodiments of the presentdisclosure, a method may include sensing temperatures at a plurality oflocations associated with an information handling system, and based onat least a power provided to a subsystem of the information handlingsystem, estimating a thermal condition proximate to the subsystem, andsetting a speed of at least one cooling fan of a cooling subsystem forgenerating a cooling airflow in the information handling system based onthe estimated thermal condition and a required linear airflow velocityassociated with the subsystem.

In accordance with these and other embodiments of the presentdisclosure, a system may include a plurality of temperature sensorsconfigured to sense temperatures at a plurality of locations associatedwith an information handling system, a cooling subsystem comprising atleast one cooling fan configured to generate a cooling airflow in theinformation handling system, and a thermal manager communicativelycoupled to the plurality of temperature sensors and the coolingsubsystem. The thermal manager may be configured to, based on at least apower provided to a subsystem of the information handling system,estimate a thermal condition proximate to the subsystem and set a speedof the at least one cooling fan based on the estimated thermal conditionand a required cubic airflow rate associated with the subsystem, whereinthe required cubic airflow rate is determined based on a required linearairflow velocity associated with the subsystem and a net cross-sectionalarea through which the cooling airflow travels.

In accordance with these and other embodiments of the presentdisclosure, a method may include sensing temperatures at a plurality oflocations associated with an information handling system and based on atleast a power provided to a subsystem of the information handlingsystem, estimating a thermal condition proximate to the subsystem, andsetting a speed of the at least one cooling fan based on the estimatedthermal condition and a required cubic airflow rate associated with thesubsystem, wherein the required cubic airflow rate is determined basedon a required linear airflow velocity associated with the subsystem anda net cross-sectional area through which the cooling airflow travels.

In accordance with these and other embodiments of the presentdisclosure, a system may include a plurality of temperature sensorsconfigured to sense temperatures at a plurality of locations associatedwith an information handling system, a cooling subsystem comprising atleast one cooling fan configured to generate a cooling airflow in theinformation handling system, and a thermal manager communicativelycoupled to the plurality of temperature sensors and the coolingsubsystem. The thermal manager may be configured to, based on at least apower provided to a subsystem of the information handling system,estimate a thermal condition proximate to the subsystem, correlate eachof a plurality of components of the subsystem and a linear airflowvelocity requirement of the component to a respective speed of the atleast one cooling fan required to provide such airflow requirement, andset a speed of the at least one cooling fan based on the respectivespeeds.

In accordance with these and other embodiments of the presentdisclosure, a method may include sensing temperatures at a plurality oflocations associated with an information handling system and based on atleast a power provided to a subsystem of the information handlingsystem, estimating a thermal condition proximate to the subsystem,correlating each of a plurality of components of the subsystem and alinear airflow velocity requirement of the component to a respectivespeed of the at least one cooling fan required to provide such airflowrequirement, and setting a speed of the at least one cooling fan basedon the respective speeds.

In accordance with these and other embodiments of the presentdisclosure, a system may include a plurality of temperature sensorsconfigured to sense temperatures at a plurality of locations associatedwith an information handling system, a cooling subsystem comprising atleast one cooling fan configured to generate a cooling airflow in theinformation handling system, and a thermal manager communicativelycoupled to the plurality of temperature sensors and the coolingsubsystem. The thermal manager may be configured to, based on at least apower provided to a subsystem of the information handling system,estimate a thermal condition proximate to the subsystem, based on amaximum power consumption for a component of the subsystem, determine anestimated linear airflow velocity requirement for the component, and seta speed of the at least one cooling fan based on the estimated thermalcondition and the estimated linear airflow velocity requirement.

In accordance with these and other embodiments of the presentdisclosure, a method comprising may include sensing temperatures at aplurality of locations associated with an information handling system,and based on at least a power provided to a subsystem of the informationhandling system, estimating a thermal condition proximate to thesubsystem, based on a maximum power consumption for a component of thesubsystem, determining an estimated linear airflow velocity requirementfor the component, and setting a speed of at least one cooling fan basedon the estimated thermal condition and the estimated linear airflowvelocity requirement.

Technical advantages of the present disclosure may be readily apparentto one skilled in the art from the figures, description and claimsincluded herein. The objects and advantages of the embodiments will berealized and achieved at least by the elements, features, andcombinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are examples and explanatory and arenot restrictive of the claims set forth in this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 illustrates a perspective view of an example information handlingsystem, in accordance with embodiments of the present disclosure;

FIG. 2 illustrates a mathematical model for estimating component thermalperformance and setting thermal controls, in accordance with embodimentsof the present disclosure;

FIG. 3 illustrates a plan view of an example information handlingsystem, in accordance with embodiments of the present disclosure;

FIG. 4 illustrates a user interface for managing thermal conditions of aserver information handling system with stored configuration settings ofsubsystems within the information handling system, in accordance withembodiments of the present disclosure;

FIGS. 5A and 5B illustrates a user interface for estimating systemairflow and exhaust temperature based upon conservation of energy withinan information handling system housing, in accordance with embodimentsof the present disclosure;

FIG. 6 illustrates a user interface for setting cooling airflow to meetdefined conditions, such as temperature defined as a fixed requirement,a measurement read from a sensor or a measurement leveraged from avirtual sensor reading, in accordance with embodiments of the presentdisclosure;

FIG. 7 illustrates a conversion of determined airflow rates to coolingfan pulse width modulation settings, in accordance with embodiments ofthe present disclosure;

FIG. 8 illustrates a flow chart of an example method for estimatingairflow in LFM based on airflow in CFM and an estimated cross-sectionalarea through which the flow of air travels, in accordance withembodiments of the present disclosure;

FIG. 9 illustrates a flow chart of an example method of slot-by-slotscaling of airflow in LFM and application thereof, in accordance withembodiments of the present disclosure;

FIG. 10 illustrates a table mapping each slot to an associated scalingfactor, in accordance with embodiments of the present disclosure;

FIG. 11 illustrates a table wherein each row depicts an exampleconfiguration of populating three cards within six slots of a PCIsubsystem and cooling fan speeds required to support such configuration,in accordance with embodiments of the present disclosure;

FIG. 12 illustrates a flow chart of an example method of performingthermal control of unqualified components, in accordance withembodiments of the present disclosure;

FIG. 13 illustrates a table with an example of mapping a form factor andlane width of a PCI card to an assumed maximum power consumption forsuch card, in accordance with embodiments of the present disclosure;

FIG. 14 illustrates a table for estimating an airflow requirement in LFMfor a card based on maximum power consumptions for different formfactors of a card and information handling system platform types forwhich such card may be installed, in accordance with embodiments of thepresent disclosure; and

FIG. 15 illustrates a table mapping a plurality of card vendors and lanewidths for cards of such vendors to an associated scaling factor, inaccordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

Preferred embodiments and their advantages are best understood byreference to FIGS. 1-15, wherein like numbers are used to indicate likeand corresponding parts.

For the purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, entertainment, or other purposes. For example, aninformation handling system may be a personal computer, a PDA, aconsumer electronic device, a network storage device, or any othersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include memory, one ormore processing resources such as a central processing unit (CPU) orhardware or software control logic. Additional components of theinformation handling system may include one or more storage devices, oneor more communications ports for communicating with external devices aswell as various input and output (I/O) devices, such as a keyboard, amouse, and a video display. The information handling system may alsoinclude one or more buses operable to transmit communication between thevarious hardware components.

For the purposes of this disclosure, computer-readable media may includeany instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), and/or flash memory; aswell as communications media such as wires, optical fibers, microwaves,radio waves, and other electromagnetic and/or optical carriers; and/orany combination of the foregoing.

For the purposes of this disclosure, information handling resources maybroadly refer to any component system, device or apparatus of aninformation handling system, including without limitation processors,buses, memories, I/O devices and/or interfaces, storage resources,network interfaces, motherboards, integrated circuit packages;electro-mechanical devices (e.g., air movers), displays, and powersupplies.

FIG. 1 illustrates a perspective view of an example information handlingsystem 10, in accordance with embodiments of the present disclosure. Asshown in FIG. 1, information handling system 10 may comprise a serverbuilt into a housing 12 that resides with one or more other informationhandling systems 10 in a rack 14. Rack 14 may comprise a plurality ofvertically-stacked slots 16 that accept information handling systems 10and a plurality of power supplies 18 that provide electrical energy toinformation handling systems 10. In a data center environment, rack 14may receive pretreated cooling air provided from a floor vent 20 to aidremoval of thermal energy from information handling systems 10 disposedin rack 14. Power supplies 18 may be assigned power based uponavailability at the data center and may allocate power to individualinformation handling systems 10 under the management of a chassismanagement controller (CMC) 22. CMC 22 may aid coordination of operatingsettings so that information handling systems 10 do not exceed thermalor power usage constraints.

Housing 12 may include a motherboard 24 that provides structural supportand electrical signal communication for processing components disposedin housing 12 that cooperate to process information. For example, one ormore central processing units (CPUs) 26 may execute instructions storedin random access memory (RAM) 28 to process information, such asresponses to server requests by client information handling systemsremote from information handling system 10. One or more persistentstorage devices, such as hard disk drives (HDD) 30 may store informationmaintained for extended periods and during power off states. A backplanecommunications manager, such as a PCI card 32, may interface processingcomponents to communicate processed information, such as communicationsbetween CPUs 26 and network interface cards (NICs) 34 that are sentthrough a network, such as a local area network. A chipset 36 mayinclude various processing and firmware resources for coordinating theinteractions of processing components, such as a basic input/outputsystem (BIOS). A baseboard management controller (BMC) 38 may interfacewith chipset 36 to provide out-of-band management functions, such asremote power up, remote power down, firmware updates, and powermanagement. For example, BMC 38 may receive an allocation of power fromCMC 22 and monitor operations of the processing components ofinformation handling system 10 to ensure that power consumption does notexceed the allocation. As another example, BMC 38 may receivetemperatures sensed by temperature sensors 40 and apply the temperaturesto ensure that thermal constraints are not exceeded.

A thermal manager 42 may execute as firmware, software, or otherexecutable code on BMC 38 to manage thermal conditions within housing12, such as the thermal state at particular processing components orambient temperatures at discrete locations associated with housing 12.Thermal manager 42 may control the speed at which cooling fans 44 rotateto adjust a cooling airflow rate in housing 12 so that enough excessthermal energy is removed to prevent an over-temperature condition, suchas overheating of a CPU 26 or an excessive exhaust temperature asmeasured by an outlet temperature sensor 40. In the event that coolingfans 44 cannot provide sufficient cooling airflow to meet a thermalconstraint, thermal manager 42 may reduce power consumption at one ormore of the processing components to reduce the amount of thermal energyreleased into housing 12, such as by throttling the clock speed of oneor more of CPUs 26. Thermal manager 42 may respond to extreme thermalconditions that place system integrity in jeopardy by shutting downinformation handling system 10, such as might happen if floor vent 20fails to provide treated air due to a data center cooling systemfailure.

In order to more effectively manage thermal conditions associated withhousing 12, thermal manager 42 may apply conservation of energy toestimate thermal conditions at discrete locations associated withinhousing 12 and then use the estimated thermal conditions for moreprecise control of the overall thermal state of information handlingsystem 10. For example, thermal manager 42 may perform one or moreenergy balances based upon available measures of power consumption,cooling fan speed, and sensed thermal conditions to estimateintermediate temperatures at discrete locations within housing 12. Theestimated intermediate temperatures may provide more precise control ofthe thermal conditions at discrete locations to maintain thermalconstraints, such as maximum ambient temperatures of components that donot include temperature sensors or maximum inlet temperatures forcomponents downstream in the cooling airflow from the estimated ambienttemperature. Estimated intermediate temperatures may be applied in anoverall system conservation of energy model so that fan speed andcomponent power consumption are determined to maintain thermalconstraints, such as maximum exhaust temperatures. Thermal manager 42may estimate discrete thermal conditions at locations within housing 12by applying available component configuration information, such as acomponent inventory kept by BMC 38, and sensed, known, or estimatedpower consumption of the components. For example, BMC 38 may use actualpower consumption of components or subassemblies if actual powerconsumption is available, known power consumption stored in the BMCinventory for known components, or estimated power consumption basedupon the type of component and the component's own configuration. Anexample of estimated power consumption is a general estimate of powerconsumption stored in BMC 38 for unknown PCI cards 32 with the generalestimate based upon the width of the PCI card, i.e., the number of linkssupported by the PCI card. In one embodiment, as estimated intermediatethermal conditions are applied to generate fan and power consumptionsettings, a self-learning function may compare expected results andmodels to component and subassembly thermal characteristics so that moreaccurate estimates are provided over time.

FIG. 2 illustrates a mathematical model for estimating component 46thermal performance and setting thermal controls, in accordance withembodiments of the present disclosure. According to the law ofconservation of energy, the total energy state of an informationhandling system is maintained as a balance of the energy into the systemand the energy out of the system. The energy balance may be broken intoa sum of a plurality of components 46 wherein each component 46 has aknown or estimated power consumption that introduces thermal energy intothe information handling system. The system energy balance becomes theenergy into the system as reflected by an airflow inlet temperature, thethermal energy released by the sum of the components 46 that consumepower in the system and the energy out of the system as reflected by anairflow exhaust temperature. Energy removed from the system may relateto the mass flow rate of air flowing through the system and thecoefficient for energy absorption of the cooling airflow. Simplified forthe coefficient that typically applies to atmospheric air, the energyreleased by electrical power consumption may be equal to airflow incubic feet per minute divided by a constant of 1.76 and multiplied bythe difference between the exhaust temperature and inlet temperature.Alternatively, again simplified for the coefficient that typicallyapplies to atmospheric air, the energy released by electrical powerconsumption may be equal to a linear airflow velocity in linear feet perminute (which may be calculated as a cubic airflow rate in cubic feetper minute multiplied by an area of an inlet of a component of interest(e.g., cross sectional area of inlet of a card)) divided by a constantof 1.76 and multiplied by the difference between the exhaust temperatureand inlet temperature. Thermal manager 42 may apply one or both of theseformulas to set cooling fan speed to meet exhaust temperatureconstraints. For internal components and subassemblies, thermal manager42 may determine a minimum fan speed to keep ambient temperature of acomponent within a desired constraint by determining an “inlet”temperature estimated for air as it arrives at the component based uponpower consumption of other components in the airflow before the airarrives at the component of interest. The increase in temperatureexhausted at the component of interest may be estimated based upon thepower consumed by the component of interest and the cooling airflowrate. Thus, a fan speed may be set that prevents an “exhaust” from thecomponent of interest that is in excess of thermal constraintsassociated with the component. Alternatively, estimated temperatures atintermediate components may be summed and applied to set a fan speedthat achieves a desired overall system thermal condition, such as anexhaust temperature constraint.

Applying conservation of energy and component power consumption tomanage thermal conditions may allow more precise control of thermalconditions and discrete control within an information handling systemhousing even where measurements of actual thermal conditions by atemperature sensor are not available. A modular energy balance thermalcontroller may allow combined serial energy balances to account for theeffect of reduced inlet temperatures when increasing speeds fordownstream energy balances. This flexibility may be provided by usingenergy balances independently to solve for either exhaust temperature orairflow on a system-wide basis or at discrete locations within a system.Subsystem power consumption based upon a component or collection ofcomponents may allow for estimation of upstream preheat for othercomponents within an information handling system housing. For example,components that do not dissipate substantial heat by power consumptionmay be scaled to have a reduced impact on airflow temperatures. Oneexample of such a component is a cooling fan, which dissipates 60 to 80%of power consumption as heat and 20 to 40% as air moving, but isgenerally ignored with conventional thermal controls. By adding fanpower and scaling to match efficiency for the system, a more precisepicture of thermal conditions within a housing may be provided.Isolating power consumption of specific regions, subsystems orcomponents of interest, such as PCI cards, may allow the power readingsfor the subsystems to include static power from non-relevant componentsthat are accounted for by subtracting a static power value. Assigningscaled values that relate heat dissipation and power consumption foreach subsystem may provide more exact estimates of thermal conditionsand more precise control of airflow and power settings based uponpreheat that occurs in the airflow as the airflow passes through thehousing. Approaching thermal management based upon a serial summation ofsubsystem thermal conditions supports the use of static values forselected subsystems to subtract thermal overhead or exclude dynamicreadings, such as to control fan speed to achieve a static readinginstead of monitoring an available dynamic reading.

Using subsystem thermal condition estimates may aid in achieving moreaccurate fan speed settings for a desired exhaust constraint sinceairflow-to-fan speed relationships are set based on actual systemconfiguration and component power consumption. Summed energy balances ofdiscrete subsystems disposed in a housing may differentiate thermalcontrol based on hardware inventory, system state, or system events toenhance control accuracy. Airflow may be scaled to account for componentcount based upon active components and functions being performed at thecomponents during control time periods. When solving for airflowsettings needed to meet a component or system-wide thermal constraint,the inlet or exhaust temperature may generally be a fixed requirementthat aligns with a temperature limit so that selectively setting staticvalues allows derivation of control values without using availabledynamic values. Dynamically calculated inlet ambient with a fixed staticexhaust ambient or a fixed inlet ambient and a dynamically calculatedexhaust ambient may provide a better estimate of system airflow. Aspower use fluctuates, feedback and feed forward control of thermalconditions based on average power consumption may dampen cooling fansetting fluctuations that occur when fan settings are made based uponinstantaneous power readings alone. Averaging measured fan speeds mayalso help to simplify correlations and to “learn” thermalcharacteristics of subsystems as thermal conditions respond over time tochanges in power consumption at various subsystems. For example, eachfan within a housing can run at different pulse width modulation (PWM)speed settings in which a speed of a fan is based on a duty cycle of aPWM signal received by the fan. Calculating an average PWM fromindividual fan PWM speed settings may allow a PWM duty cycle to airflowrelationship. During operating conditions that have limited availabilityof dynamically sensed thermal conditions, such as at startup, during fanfailure, during sensor failure, and during baseline cooling, estimatedsubsystem thermal conditions based upon subsystem power consumption mayprovide a model for fan speed settings. Generally, fan speed settingcontrol based upon a summation of estimated and/or actual subsystemthermal conditions may allow defined minimum fan speeds for asystem-wide constraint with supplemental cooling of critical componentsbased on closed loop feedback.

FIG. 3 illustrates a plan view of example information handling system10, in accordance with embodiments of the present disclosure. Externalair drawn into information handling system 10 may have an ambienttemperature (T_(AMBIENT)) measured by an inlet temperature sensor 40 andan airflow rate determined by the speed at which one or more coolingfans spin. As the cooling airflow passes through housing 12, it mayabsorb thermal energy resulting in a preheat of the airflow fordownstream components. The cooling airflow may be forced frominformation handling system 10 at an exhaust with an exhaust temperature(T_(EXHAUST)) fixed at thermal constraint (e.g., 70° C.) as arequirement and/or measured by an exhaust temperature sensor 40. Thermalmanager 42 may adapt cooling fan speed so that the cooling airflowtemperature T_(EXHAUST) maintains a thermal constraint (e.g., 70° C.)

As shown in FIG. 3, a virtual thermal sensor 48 may be generated bythermal manager 42 at a location in information handling system 10 thatreceives preheated airflow, such as airflow that has passed by CPUs 26.Thermal manager 42 may apply configuration information stored in BMC 38to determine the components that preheat airflow to virtual thermalsensor 48 and may determine power consumed by the components to arriveat a virtual temperature measured by virtual thermal sensor 48. Forexample, thermal manager 42 may apply power consumed by CPUs 26 andstatic power consumption associated with other preheat components todetermine by conservation of energy the ambient temperature of airexhausted from CPUs 26 to arrive at the virtual temperature. The virtualtemperature may then be used as an inlet temperature to a PCI cardsubsystem 32 so that an ambient temperature of PCI card subsystem 32 iscomputed based upon energy consumed by PCI card subsystem 32. PCI cardsubsystem 32 may exhaust air at temperature T_(EXHAUST) measured byexhaust sensor 40 so that control of the ambient temperature within PCIcard subsystem 32 provides control of the overall system exhaust. Theincrease in thermal energy caused by PCI card subsystem 32 as reflectedby the increase from the virtual temperature to the exhaust temperaturemay be estimated using conservation of energy applied to the energyconsumption of PCI card subsystem 32. Generally, PCI card subsystem 32power consumption may be measured directly based upon power assigned bya power subsystem or estimated with a static value. Alternatively, powerconsumption may be derived from estimates using conservation of energyapplied to known power consumption and thermal conditions in housing 12.Thus, the power consumed by PCI card subsystem 32 may be dynamicallydetermined by actual measurements of power usage, by stored power usagebased on the inventory of the PCI card maintained in the BMC, or by anestimate of power consumption based upon characteristics of the PCIcard, such as the width of the PCI card.

Having one or more intermediate virtual thermal sensors 48 may provideflexibility in managing system operation by using a virtual temperaturemeasurement as a dynamic thermal control input or a static thermalcontrol constraint. For example, if PCI card subsystem 32 is controlledto have a static value of 50° C., then fan speed and CPU powerconsumptions may be adjusted to maintain that value. If T_(ExHAUST) hasa constraint of 70° C., then excessive temperatures might occur duringlow CPU power usage due to low fan speed settings needed to maintain the50° C. virtual thermal sensor 48 measurement and temperature increasesof greater than 20° C. from PCI card power consumption. In such aninstance, if precise power control is available for desired components,thermal control might focus on T_(EXHAUST) so that the virtualtemperature falls below 50° C. or might focus on power consumption byPCI card subsystem 32 so that less thermal energy is released aftervirtual thermal sensor 48. Typically, PCI card subsystems do not at thistime allow control of thermal energy release, such as by throttling aprocessor clock, however, such capabilities may be introduced for PCIcards or other components in the future. Discrete control of thermalconditions at different locations within information handling system 10may be provided by generating virtual thermal sensors at the desiredlocations and then selectively treating the values as dynamic or staticfor control purposes.

FIG. 4 illustrates a user interface for managing thermal conditions of aserver information handling system with stored configuration settings ofsubsystems within the information handling system, in accordance withembodiments of the present disclosure. Energy balance table 50 mayinclude energy balance parameters for components integral to informationhanding system 10 as well as estimated values for potential replacementcomponents, such as non-specific PCI cards having a width of four oreight lanes. By including configuration match information that relatescomponents to energy consumption, thermal manager 42 may be able toestimate a thermal condition based on detected components and energybalance information associated with such detected components as setforth in energy balance table 50.

FIGS. 5A and 5B illustrate a user interface for estimating systemairflow and exhaust temperature based upon conservation of energy withinan information handling system housing, in accordance with embodimentsof the present disclosure. An exhaust temperature energy balance table52 may apply power, cubic airflow, linear airflow velocity, and sensedtemperature values to estimate thermal states and set control fordesired cubic airflow, linear airflow velocity, and temperatureparameters. A power window 54 may depict a power dissipation calculationperformed for each subsystem having an energy balance number in energybalance table 50. A total system power dissipation may represent poweruse by all desired components, which in this example embodiment mayinclude one or more cooling fans. Scaling factors may be set to adjustthe relative power consumption in various configuration modes inresponse to dynamic power settings. A static power setting may alsoallow control to achieve a desired power setting at a component. A cubicairflow window 56 depicts a mass flow calculation cubic feet per minute(CFM) and a linear airflow velocity window 57 depicts a linear airflowvelocity in linear feet per minute (LFM) for determination of cubicairflow or linear airflow velocity to achieve the energy balance withthe determined power settings for each component. The example embodimentdepicted by FIGS. 5A and 5B may estimate cubic airflow, linear airflowvelocity, and exhaust temperatures, including with virtual temperaturesensors. In particular, for a given PWM value associated with coolingfans, exhaust temperature energy balance table 52 may correlate such PWMvalue to an estimated cubic airflow (e.g., in CFM) and/or an estimatedlinear airflow velocity (e.g., in LFM) for configurations associatedwith the energy balance number.

Although FIG. 5B shows estimation of linear airflow velocity based oncorrelation from PWM values, in some embodiments, linear airflowvelocity may be determined from the PWM-to-cubic airflow ratecorrelation, by dividing the cubic airflow rate correlated to a PWMvalue by an inlet area of a component of interest (e.g., card). FIG. 7described below may provide mass airflows converted to cooling fan PWMvalues to assign cooling fan rotation speeds based upon individualcomponent configurations adjusted for scaling.

FIG. 6 illustrates a user interface for setting cooling airflow to meetdefined conditions, such as temperature defined as a fixed requirement,a measurement read from a sensor, or a measurement leveraged from avirtual sensor reading, in accordance with embodiments of the presentdisclosure. The user interface of FIG. 6 may be used by thermal manager42 to compute how much airflow is required to cool a component. Thetemperature and power values may be static or dynamic; however, onevalue may be set to static to support control of the other values tomeet a targeted static condition. An airflow energy balance table 60 maysupport mass airflow and exhaust temperature estimates with dynamic orstatic settings in the power consumption of the components. An averagenumber of readings input aids in adjusting for thermal lag related todelays between dissipation of power by components and temperatureimpacts. In the entry for energy balance number EB4 shown in FIG. 6, anexhaust temperature of 70° C. may be set for exhaust from a PCI cardbased upon a static power setting for a lane width of eight lanes. Forexample, a lane width of eight lanes may define an estimated powerconsumption for the card and the 70° C. temperature may define anoverall system safety constraint. The entry sets a static inlettemperature for the PCI card of 55° C., such as might be an input limitfor the PCI card or so that an airflow rate is determined that maintainsthe desired exhaust temperature constraint. Alternatively, the inlettemperature may be dynamic from a physical sensor or from a virtualsensor computed with a conservation of energy estimated based uponupstream component power consumption. If the airflow rate is less thananother airflow rate required at a different location in housing 12, theconstraint may be met without applying the determined airflow rate. Forexample, if the airflow rate to maintain 55° C. exhaust from the CPUs isgreater than the airflow rate required to maintain PCI card thermalconditions, then the CPU airflow rate will apply. In this manner,discrete airflow rates for different portions of information handlingsystem 10 may provide more exact thermal management for componentsdisposed within housing 12.

FIG. 7 illustrates a user interface table 62 for conversion ofdetermined airflow rates to cooling fan pulse width modulation (PWM)settings, in accordance with embodiments of the present disclosure. Forexample, a graph of different levels of cooling airflow and PWM settingsare depicted for different numbers of hard disk drives disposed inhousing 12. Such data may be used to set a scaling factor (value of0.008 under the heading “HDD”) in an energy balance entry for aparticular energy balance number. Thus, given a particular airflowrequirement, whether in CFM or LFM, required cooling fan speeds may becalculated based upon system configuration as detected by BMC 38.

Using the foregoing methods and systems, a cubic airflow rate or linearairflow velocity at a particular point (e.g., at an inlet of PCIsubsystem 32) in information handling system 10, may be estimated basedon cooling fan speed. Such cubic airflow rate or linear airflow rate maybe a “bulk” or average value (e.g., a per PCI slot average value) or aworst case rate (e.g., an value for a “worst case” PCI slot PCIsubsystem 32). In addition, using the foregoing methods and systems,given a required cubic airflow rate or linear airflow velocity for acomponent (e.g., a PCI card), a minimum fan speed required to supportsuch component may be estimated.

While the foregoing description contemplates using energy balances toestimate a linear airflow velocity in LFM based on a cooling fan PWMvalue, linear airflow velocity in LFM may also be estimated by using anestimate of cubic airflow rate in CFM (e.g., generated using energybalance data from table 52 in FIG. 5) and an estimated cross-sectionalarea through which the flow of air travels, as described below withrespect to FIG. 8.

FIG. 8 illustrates a flow chart of an example method 800 for estimatinglinear airflow rate in LFM based on cubic airflow rate in CFM and anestimated cross-sectional area through which the flow of air travels, inaccordance with embodiments of the present disclosure. According to someembodiments, method 800 may begin at step 802. As noted above, teachingsof the present disclosure may be implemented in a variety ofconfigurations of information handling system 10. As such, the preferredinitialization point for method 800 and the order of the stepscomprising method 800 may depend on the implementation chosen.

At step 802, thermal manager 42 may, based on a component inventory(e.g., as maintained by BMC 38), determine an estimate ofcross-sectional area which is blocked to airflow within informationhandling system 10. For example, the component inventory met set forth anumber of PCI slots in PCI subsystem 32 and which of such PCI slots arepopulated and the type of PCI card populated (e.g., whether a card islow-profile or full-height, and/or a lane width of the card). Based onthis inventory and known, estimated, or assumed physical dimensions ofthe PCI slots and the PCI cards populating the slots, thermal manager 42may estimate a cross-sectional area of PCI components that would blockairflow through information handling system 10. In addition, similarestimates may be made with respect to other components and/or systems(e.g., power supply unit inventory, network card inventory, etc.) todetermine their respective cross section area that would block airflowthrough information handling system 10. Thermal manager 42 may aggregatethe respective cross-sectional areas of all such components andsubsystems to determine the overall estimate of cross-sectional areawhich is blocked to airflow within information handling system 10.

At step 804, thermal manager 42 may, based on a form factor of rack 14,slot 16, and housing 12, determine a gross cross-sectional area of theform factor of information handling system 10, which may essentially bea cross-sectional area of information handling system 10 through whichair would flow in the absence of blockage by components accounted for instep 802 above.

At step 806, thermal manager 42 may subtract the estimatedcross-sectional area which is blocked to airflow from the grosscross-sectional area to determine an estimated net cross-sectional areathrough which air may flow in information handling system 10.

At step 808, thermal manager 42 may determine a net system cubic airflowrate in CFM. In some embodiments, such net system cubic airflow rate maybe determined in accordance with energy balance data from table 52 inFIG. 5 to correlate speed of a cooling fan to cubic airflow rate in CFM,as described in greater detail above.

At step 810, thermal manager 42 may divide the net cubic system airflowrate by the estimated net cross-sectional area to determine an estimatedaverage linear airflow velocity in LFM. After completion of step 810,method 800 may end.

Although FIG. 8 discloses a particular number of steps to be taken withrespect to method 800, method 800 may be executed with greater or fewersteps than those depicted in FIG. 8. In addition, although FIG. 8discloses a certain order of steps to be taken with respect to method800, the steps comprising method 800 may be completed in any suitableorder.

Method 800 may be implemented using one or more information handlingsystems 10, components thereof, and/or any other system operable toimplement method 800. In certain embodiments, method 800 may beimplemented partially or fully in software and/or firmware embodied incomputer-readable media.

Although the foregoing methods and systems permit estimation of anaverage or worst case linear airflow velocity in LFM based on a coolingfan speed and estimation of a required cooling fan speed based on aworst-case LFM-based required linear airflow velocity, slot-by-slotairflow estimation may be performed by applying per-slot scaling factorsbased on an inventory of each slot (e.g., for PCI slots, whether theslot is populated with a card, whether the card is low-profile orfull-height, and/or a lane width of the card) to the average orworst-case LFM estimates. Accordingly, linear airflow velocity may beoptimized on a slot-by-slot basis instead of cooling fan speed being setbased on a worst-case linear airflow velocity requirement, which mayreduce required airflow needed to support airflow velocity requirementsof cards, and thus decrease power consumption needed to generaterequired cooling.

FIG. 9 illustrates a flow chart of an example method 900 of slot-by-slotscaling of linear airflow rate in LFM and application thereof, inaccordance with embodiments of the present disclosure. According to someembodiments, method 900 may begin at step 902. As noted above, teachingsof the present disclosure may be implemented in a variety ofconfigurations of information handling system 10. As such, the preferredinitialization point for method 900 and the order of the stepscomprising method 900 may depend on the implementation chosen.

At step 902, thermal manager 42 may determine a bulk (e.g., worst caseor average) system airflow velocity in LFM. In some embodiments, suchnet system airflow velocity may be determined in accordance with energybalance data from table 52 in FIG. 5 to correlate speed of a cooling fanto airflow velocity in LFM, as described in greater detail above. Inother embodiments, such net system airflow velocity may be determinedbased on a net system airflow in CFM and a net cross-sectional area forthe airflow, as described above with respect to method 800. In yet otherembodiments, such net system airflow velocity may be determined based ona correlation of PWM to linear airflow velocity for a particular (e.g.,worst case) slot.

At step 904, thermal manager 42 may, based on a component inventory(e.g., as maintained by BMC 38), identify slots (e.g., PCI slots)populated within information handling system 10 and the type of PCI cardpopulated (e.g., whether a card is low-profile or full-height, and/or alane width of the card).

At step 906, based on this identification and known, estimated, orassumed characteristics of the inventoried components, thermal manager42 may map each slot to a corresponding scaling factor. FIG. 10illustrates a table mapping each slot to an associated scaling factor,in accordance with embodiments of the present disclosure. A scalingfactor for a slot may be based on a location of the slot withininformation handling system 10, a form factor of a card populating aslot (e.g., low-profile or full-height), a lane width of a cardpopulating a slot, and/or any other characteristic of the slot or a cardpopulating such slot. In some embodiments, mathematical correlationsbetween characteristics of a slot (e.g., location, form factor, lanewidth, etc.) and the slot's scaling factor may be made based oncharacterization testing of information handling system 10 (e.g.,testing performed on a sample population of information handling systems10 by a manufacturer, vendor, or other provider of information handlingsystems 10).

At step 908, thermal manager 42 may estimate a linear airflow velocityin LFM for each slot by applying each slot's respective scaling factorto the bulk system linear airflow velocity.

At step 910, in some embodiments, such estimated per-slot linear airflowvelocities may be displayed to an administrator or other user ofinformation handling system 10 (e.g., via a management console coupledto BMC 38).

At step 912, thermal manager 42 may compare each estimated per-slotlinear airflow velocity against a required linear airflow velocity for acard populated in the slot, and if additional linear airflow velocity isrequired, thermal manager 42 may request an increase in cooling fanspeed. In some embodiments, a fan speed required for a slot may bedetermined by applying its per-slot scaling factor to determine a bulklinear airflow velocity, and then convert such bulk linear airflowvelocity to a corresponding cooling fan speed, as described above withrespect to FIG. 7.

At step 914, thermal manager 42 may compare cooling fan speedrequests/requirements for the various subsystems of information handlingsystem 10, including a per-slot speed request/requirement as determinedabove, and set a cooling fan speed based on the highest fan speedrequested.

At step 916, thermal manager 42 may use the slot-by-slot linear airflowvelocity data and based thereon, recommend to an administrator or otheruser of information handling system 10 (e.g., via a management consolecoupled to BMC 38) an optimized or improved PCI card arrangement in theslots of PCI subsystem 32, either as a guide before an administrator orother user installs one or more cards or as an optimization/improvementfor an already-populated PCI subsystem 32. In these and otherembodiments, thermal manager 42 may create a dynamic slot priority listbased on optimum cooling parameters that displays to an administrator orother user an optimum card placement based on real-time systemconfiguration and ambient conditions. FIG. 11 illustrates a tablewherein each row depicts an example configuration of populating threecards within six slots of a PCI subsystem and cooling fan speedsrequired to support such configuration, in accordance with embodimentsof the present disclosure. Notably, in the second and third exampleconfigurations, in which either of CARD2 or CARD3 are populated in SLOT1, cooling fans at their maximum speed would be unable to providesufficient airflow to satisfy linear airflow velocity requirements ofsuch configurations. Accordingly, if an administrator or other userconfigured a PCI subsystem in such manner, thermal manager 42 may issuean alert to such administrator or other user that such configuration isnot supported by the thermal capabilities of information handling system10. Also of note, the fourth configuration requires the least amount ofpower. Thus, where an administrator or other user has populated or plansto populate CARD1, CARD2, and CARD3 into a PCI subsystem, thermalmanager 42 may, in accordance with method 900, recommend the fourthconfiguration to the administrator or other user.

After completion of step 916, method 900 may end.

Although FIG. 9 discloses a particular number of steps to be taken withrespect to method 900, method 900 may be executed with greater or fewersteps than those depicted in FIG. 9. In addition, although FIG. 9discloses a certain order of steps to be taken with respect to method900, the steps comprising method 900 may be completed in any suitableorder.

Method 900 may be implemented using one or more information handlingsystems 10, components thereof, and/or any other system operable toimplement method 900. In certain embodiments, method 900 may beimplemented partially or fully in software and/or firmware embodied incomputer-readable media.

Although the foregoing methods and systems permit thermal controlrelating to components which have been qualified as to their coolingneeds by a manufacturer, vendor, or other provider of informationhandling system 10, the methods and systems described above may alone beinsufficient to apply the approaches thereof to components which havenot been qualified.

FIG. 12 illustrates a flow chart of an example method 1200 of performingthermal control of unqualified components, in accordance withembodiments of the present disclosure. According to some embodiments,method 1200 may begin at step 1202. As noted above, teachings of thepresent disclosure may be implemented in a variety of configurations ofinformation handling system 10. As such, the preferred initializationpoint for method 1200 and the order of the steps comprising method 1200may depend on the implementation chosen.

At step 1202, in response to a slot of PCI subsystem 32 being populatedwith a card which has not been qualified or characterized by amanufacturer, vendor, or other provider of information handling system10, thermal manager 42 may determine if the card's airflow requirementin LFM is otherwise known. For example, such information might beobtained via a user interface wizard in which an administrator or otheruser of information handling system 10 enters information about theunqualified card. As another example, such information might be obtainedfrom a configuration space (e.g., a PCI configuration space) or similarstorage media integral to the card. As a further example, suchinformation might come from a whitelist stored within BMC 38. If thecard's airflow requirement is known, method 1200 may proceed to step1218. Otherwise, method 1200 may proceed to step 1204.

At step 1204, thermal manager 42 may determine if the card is anactively cooled device which has its own cooling fan. For example, suchinformation might be obtained via a user interface wizard in which anadministrator or other user of information handling system 10 entersinformation about the unqualified card. As another example, suchinformation might be obtained from a configuration space (e.g., a PCIconfiguration space) or similar storage media integral to the card. Ifthe card is actively cooled, method 1200 may end as no additional fancooling may be required for the card in addition to its active coolingsystem. Otherwise, method 1200 may proceed to step 1206.

At step 1206, thermal manager 42 may determine if the card's maximumpower consumption is otherwise known. For example, such informationmight be obtained via a user interface wizard in which an administratoror other user of information handling system 10 enters information aboutthe unqualified card. As another example, such information might beobtained from a configuration space (e.g., a PCI configuration space) orsimilar storage media integral to the card. If the card's airflowrequirement is known, method 1200 may proceed to step 1210. Otherwise,method 1200 may proceed to step 1208.

At step 1208, in response to the LFM airflow requirement and maximumpower consumption of the card being unknown, thermal manager 42 may,based on a form factor, lane width, and/or other characteristics of thecard, determine an assumed maximum power consumption for such card. FIG.13 illustrates a table with an example of mapping a form factor and lanewidth of a PCI card to an assumed maximum power consumption for suchcard, in accordance with embodiments of the present disclosure.

At step 1210, thermal manager 42 may, based on an assumed maximum powerconsumption for such card (as determined at step 1208) or a knownmaximum power consumption (as determined at step 1206) determine anestimated LFM airflow requirement for the card. In some embodiments,such determination may be made by correlating the maximum powerassumption to the estimated LFM airflow based on one or morecharacteristics of the card, including a form factor of the card and aplatform type of the information handling system in which the PCI cardis installed. FIG. 14 illustrates a table for estimating an airflowrequirement in LFM for a card based on maximum power consumptions fordifferent form factors of a card and information handling systemplatform types for which such card may be installed, in accordance withembodiments of the present disclosure.

At step 1212, thermal manager 42 may determine whether a vendor of thecard is known. For example, such information might be obtained via auser interface wizard in which an administrator or other user ofinformation handling system 10 enters information about the unqualifiedcard. As another example, such information might be obtained from aconfiguration space (e.g., a PCI configuration space) or similar storagemedia integral to the card. If a vendor of the card is known, method1200 may proceed to step 1214. Otherwise, method 1200 may proceed tostep 1216.

At step 1214, in response to the vendor of the card being known, thermalmanager 42 may scale the estimated LFM airflow requirement for the cardby a vendor-based scaling factor. Thus, while the estimated LFM airflowrequirement as calculated at step 1210 may assume a “worst-case” vendor,scaling with a vendor-based scaling factor for known vendors with knowngeneral cooling requirements, thermal manager 42 may provide a betterestimate of a true airflow requirement for the card than that of theworst-case estimate of step 1210. FIG. 15 illustrates a table mapping aplurality of card vendors and lane widths for cards of such vendors toan associated scaling factor, in accordance with embodiments of thepresent disclosure.

At step 1216, thermal manager 42 may scale the estimated airflowrequirement (determined at step 1210 or step 1214) based on a per-slotscaling factor, in a manner similar to that of method 900. In someembodiments, such scaling may not be applied, and instead a bulk LFMairflow (e.g., determined at step 1210 or step 1214) may be used.

At step 1218, thermal manager 42 may determine from the LFM airflowrequirement, whether a known airflow requirement (as determined at step1202) or an estimated airflow requirement (as determined at step 1210,step 1214, or step 1216) a fan speed required for the unqualified cardby converting such LFM airflow to a corresponding cooling fan speed, asdescribed above with respect to FIG. 7.

At step 1220, thermal manager 42 may compare cooling fan speedrequests/requirements for the various subsystems of information handlingsystem 10, including a speed request/requirement for the unqualifiedcard as determined above, and set a cooling fan speed based on thehighest fan speed requested.

Although FIG. 12 discloses a particular number of steps to be taken withrespect to method 1200, method 1200 may be executed with greater orfewer steps than those depicted in FIG. 12. In addition, although FIG.12 discloses a certain order of steps to be taken with respect to method1200, the steps comprising method 1200 may be completed in any suitableorder.

Method 1200 may be implemented using one or more information handlingsystems 10, components thereof, and/or any other system operable toimplement method 1200. In certain embodiments, method 1200 may beimplemented partially or fully in software and/or firmware embodied incomputer-readable media.

Thus, in accordance with method 1200, thermal manager 42 may, based onlimited or incremental knowledge and/or information about an unqualifiedcomponent, make the best estimation possible regarding the thermalbehavior of such component.

The systems and methods described above may provide many advantages. Forexample, the systems and methods above may provide for determination ofwhether a required LFM flow rate for a card is supported by a thermalmanagement system of an information handling system, and provide analert if a card is not supported. As another example, the systems andmethods allow for reporting to an administrator or other user real-time,system maximum and system minimum LFM airflow values within managementinterfaces of an information handling system 10, including on aslot-by-slot basis. As a further example, the systems and methods mayenable setting of custom cooling fan speed options in terms of requiredLFM airflow, including on a slot-by-slot basis. Moreover, the systemsand methods may allow for reporting of optimum card configurations inorder to ensure that cards are inserted in slots for which adequate LFMairflow can be provided as well as optimizing power consumption based onslot-based determinations of required LFM airflow. Additionally, thesystems and methods may allow for such advantages to be applied not onlyto cards that are qualified by a vendor, manufacturer, or other providerof an information handling system, but also to unqualified cards basedon administrator or other user input or assumption regarding such cards.

Although the foregoing discusses cubic airflow in terms of cubic feetper minute, other units of measurement may be used (e.g., cubic metersper second). Also, although the foregoing discusses linear airflowvelocity in terms of linear feet per minute, other units of measurementmay be used (e.g., meters per second).

As used herein, when two or more elements are referred to as “coupled”to one another, such term indicates that such two or more elements arein electronic communication or mechanical communication, as applicable,whether connected indirectly or directly, with or without interveningelements.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Similarly,where appropriate, the appended claims encompass all changes,substitutions, variations, alterations, and modifications to the exampleembodiments herein that a person having ordinary skill in the art wouldcomprehend. Moreover, reference in the appended claims to an apparatusor system or a component of an apparatus or system being adapted to,arranged to, capable of, configured to, enabled to, operable to, oroperative to perform a particular function encompasses that apparatus,system, or component, whether or not it or that particular function isactivated, turned on, or unlocked, as long as that apparatus, system, orcomponent is so adapted, arranged, capable, configured, enabled,operable, or operative.

All examples and conditional language recited herein are intended forpedagogical objects to aid the reader in understanding the disclosureand the concepts contributed by the inventor to furthering the art, andare construed as being without limitation to such specifically recitedexamples and conditions. Although embodiments of the present disclosurehave been described in detail, it should be understood that variouschanges, substitutions, and alterations could be made hereto withoutdeparting from the spirit and scope of the disclosure.

What is claimed is:
 1. A system comprising: a plurality of temperaturesensors configured to sense temperatures at a plurality of locationsassociated with an information handling system; a cooling subsystemcomprising at least one cooling fan configured to generate a coolingairflow in the information handling system; and a thermal managercommunicatively coupled to the plurality of temperature sensors and thecooling subsystem and configured to: based on at least a power providedto a subsystem of the information handling system, estimate a thermalcondition proximate to the subsystem; based on a maximum powerconsumption for a component of the subsystem, determine an estimatedlinear airflow velocity requirement for the component; and set a speedof the at least one cooling fan based on the estimated thermal conditionand the estimated linear airflow velocity requirement.
 2. The system ofclaim 1, wherein the maximum power consumption is an assumed maximumpower assumption based on characteristics of a component of thesubsystem.
 3. The system of claim 2, wherein each of the componentscomprises a slot, and characteristics of the component include at leastone of whether the slot is populated, a form factor of a card populatingthe slot, and a lane width of the card populating the slot.
 4. Thesystem of claim 2, wherein the estimated linear airflow velocityrequirement is based on a non-vendor specific estimated airflowrequirement for the component scaled by a vendor-based scaling factor.5. The system of claim 4, wherein the vendor-based scaling factor isbased on a vendor of the component and at least one characteristic ofthe component.
 6. The system of claim 5, wherein the component is a slotof the subsystem, and the at least one characteristic comprises a lanewidth of a card populated in the slot.
 7. The system of claim 2, whereinthe component is a slot of the subsystem, and wherein the estimatedlinear airflow velocity requirement is based on a bulk estimated airflowrequirement for the component scaled by a slot-based scaling factor. 8.The system of claim 7, wherein the slot-based scaling factor is based onat least one characteristic of the component and a component inventoryof the subsystem.
 9. The system of claim 8, wherein the at least onecharacteristic of the component includes at least one of whether theslot is populated, a form factor of a card populating the slot, and alane width of the card populating the slot.
 10. A method comprising:sensing temperatures at a plurality of locations associated with aninformation handling system; and based on at least a power provided to asubsystem of the information handling system: estimating a thermalcondition proximate to the subsystem; based on a maximum powerconsumption for a component of the subsystem, determining an estimatedlinear airflow velocity requirement for the component; and setting aspeed of at least one cooling fan based on the estimated thermalcondition and the estimated linear airflow velocity requirement.
 11. Themethod of claim 10, wherein the maximum power consumption is an assumedmaximum power assumption based on characteristics of a component of thesubsystem.
 12. The method of claim 11, wherein each of the componentscomprises a slot, and characteristics of the component include at leastone of whether the slot is populated, a form factor of a card populatingthe slot, and a lane width of the card populating the slot.
 13. Themethod of claim 11, wherein the estimated linear airflow velocityrequirement is based on a non-vendor specific estimated airflowrequirement for the component scaled by vendor-based scaling factor. 14.The method of claim 13, wherein the vendor-based scaling factor is basedon a vendor of the component and at least one characteristic of thecomponent.
 15. The method of claim 14, wherein the component is a slotof the subsystem, and the at least one characteristic comprises a lanewidth of a card populated in the slot.
 16. The method of claim 11,wherein the component is a slot of the subsystem, and wherein theestimated linear airflow velocity requirement is based on a bulkestimated airflow requirement for the component scaled by a slot-basedscaling factor.
 17. The method of claim 16, wherein the slot-basedscaling factor is based on at least one characteristic of the componentand a component inventory of the subsystem.
 18. The method of claim 17,wherein the at least one characteristic of the component includes atleast one of whether the slot is populated, a form factor of a cardpopulating the slot, and a lane width of the card populating the slot.